It is well known in the manufacture of glass units for placement within windows and door frames to use single or multi-pane units that include insulating material at the peripheral edges thereof. One conventional method of making a double-glazed insulated glass panel consists of manually applying an adhesive strip along the peripheral edges of a glass sheet and then positioning a second glass sheet thereupon to form the panel.
One type of strip used in such a system is manufactured by TREMCO MANUFACTURING under the trademark "Swiggle Strip". This preferred sealant strip is an adhesive strip which is formed of an extruded butyl-based material of a thermoplastic compound which contains a reinforcing aluminum spacer to withstand the forces applied perpendicularly to the sheets of glass that are eventually joined together with the sealant strip therebetween.
Typically, the swiggle strip is applied to the first sheet of glass by a hand held applicator device such as that shown in U.S. Pat. No. 5,013,377. The device is adapted to move on a support table and to generally remain in an upright position but the proper application of the sealant strip requires skill and attention.
U.S. Pat. No. 5,246,331 discloses an air flotation assembly table that allows a sheet of glass to be conveniently moved and aligned toward a front working area. However, the application of the strip along the edges of a sheet of glass still requires skill and attention for the strip be properly positioned and aligned. If not done properly, the strip might be positioned inwardly from the edge in some locations and would be unacceptable if it appears uneven at the edge of the framing material after assembly. There is particularly concern during the application of the strip at the corners to insure that the strip is applied at a tight right angle. If not, the strip will be clearly seen after assembly.
U.S. Pat. No. 5,433,818 discloses apparatus for turning a sheet-like workpiece, e.g. a rectangular sheet of glass, and for applying a sealing strip continuously along its edges. The apparatus includes an air flotation support bed covered by an air-permeable mat, a sealing strip applicator in a carriage, suction cup assemblies mounted for movement on respective mutually perpendicular slides for gripping the sheet at two adjacent corners thereof. The movement of the assemblies is co-ordinated such that, while gripping the sheet, one assembly is moved towards the initial position of the other assembly and simultaneously the latter is moved towards the corner diagonally opposite that at which the first assembly was initially disposed.
While the apparatus of U.S. Pat. No. 5,433,818 attempts to automatically apply the sealing strip to the edges of a sheet of glass, the overall configuration is quite complicated and would be relatively expensive to provide. Additionally, the overall configuration is such that only rectangular sheets of glass can be employed. Because of the obvious limitations of this and other devices in the prior art, there remains a need for any system that can be employed to conveniently and reliably apply a sealant strip to a sheet of glass that includes any number of straight edges with corners therebetween. Such a system should be able to work effectively around corners that need not be at right angles as is required with the apparatus of U.S. Pat. No. 5,433,818.